Quality Resource Guide

Radiographic Quality Assurance for Film Imaging Systems 7th Edition

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become visually evident. Doors should also be

equipped with a lock or sign indicating “Processing

in Progress.”

Safelights

Each darkroom should be equipped with safelights

that must be used while film processing. The

safelights should be mounted at least 4 feet from

the work area. The safelight filter must provide

adequate protection based on the film sensitivity.

D-speed film must use at least an amber-colored

filter such as Kodak ML2. F-speed and extraoral

films require a red-colored filter such as the Kodak

GBX. No more than a 15-watt bulb should be used

for safelights directed at the work area.

To determine if the safelights are safe from causing

film fog, each should be checked monthly. With the

normal overhead lighting off, check the safety of

the safelight by placing a coin on top of an opened

unexposed film for 3 to 4 minutes. Then process

the film using normal processing procedures. If an

image of the coin (light circle) appears on the film,

then the filter, bulb, or distance of the mounted

safelight is not safe for processing. Filters may

need replacement approximately every two years if

used daily for 1 to 2 hours.

Automatic processors with daylight loaders should

also be evaluated for safety of the filter. If the

processor is positioned under fluorescent lighting

with an amber-colored filter, then film fogging

may occur from the white light. With the filter in

place, it may be tested in the same manner as the

safelight by placing a coin on top of an opened

unexposed film in the daylight loader. After 3 to

4 minutes, process the film in a normal manner.

The appearance of a circular image will indicate

inadequate filtering.

Processing Technique

Manual Processing

The time/temperature method should be used

for manual processing. Film emulsion contains

certain properties that are activated only if the

appropriate temperature and time are used. Thus,

assessment of when the development process is

completed should be accomplished by following

the prescribed time/temperature guidelines and

not by visual assessment. Ideally, radiographs

A quality assurance program is an important means

used by health professionals to assist them in

rendering the best care possible to the patient. In

dental radiography, quality assurance can assist in

decreasing the dose to the patient and operator as

well as providing a high-quality diagnostic images.

This Guide will review industry recognized quality

assurance standards for the darkroom and dental

operatory.

Dark Room Design

The darkroom should have a layout that is

conducive for efficient processing of radiographs

while

maintaining

proper

infection

control

procedures. Adequate counter space should allow

for unwrapping film packets and mounting films on

a film rack, if manual processing, or have adequate

space to accommodate an automatic processor.

The room must have hot and cold running water

with drainage in order to maintain appropriate

processing

temperatures

for

the

developer.

Processing chemicals should be stored in a cool

dry area. The floor should be kept clear of boxes,

etc. to prevent accidental tripping while the lights

are out. Racks or film dryers should be available

to allow radiographs to adequately dry. Because

unexposed film is extremely sensitive to heat,

humidity and background radiation, care should be

taken to store unexposed

films properly. The room

should be well ventilated to prevent chemical fume

contamination, in addition to being regulated at a

moderate temperature (50-70°F) with a 30 to 50

percent relative humidity level. Extreme humidity

levels, high or low, can create conditions that cause

moisture contamination or static electricity.

Light Leaks

The darkroom should be secured in a manner

to prevent extraneous light from entering while

processing. Areas that are common culprits include

doorjambs, keyholes, openings around water pipes,

and lighted buttons on a telephone. Doors that

cannot be locked while processing can also be a

source.

To test for light leaks, stand in the darkroom with

all lights turned off (including safelights) and doors

closed. Allow at least 1 to 2 minutes for your eyes

to become adjusted to the dark. Light leaks will

are processed for 4½ minutes at 70° F. Films

should then be agitated for 30 seconds in the rinse

water, fixed for 2 to 4 minutes and then washed

for 10 minutes or manufacturer’s guidelines. A

time/temperature chart should be posted in the

darkroom for easy reference.

The chemicals should be replenished daily.

According to the manufacturer’s recommendations

and radiographic workload, chemicals should be

discarded appropriately (see Waste Management

section) and new chemicals replaced. Records

should be kept to track cleaning and chemical

replacement.

Automatic Processing

The

automatic

processor

requires

minimal

maintenance, but regular care is a must. If cared

for according to manufacturer’s instructions, then

consistent high-quality films will be produced.

Components that should be cleaned or monitored

regularly include the tanks, rollers, solution levels,

water reservoir, and temperature. The roller

transport mechanism should be removed and

cleaned according to instructions as well as the

tanks that hold the chemicals. Water and chemical

levels should be checked daily to replenish

evaporated and depleted solutions.

The chemicals for the automatic processor differ

from those used in manual processing because

they are designed to process quickly at high

temperatures. Thus, only chemicals designed for

use in an automatic processor should be used.

When replacing and replenishing chemicals, it is

imperative to place the developer and fixer tanks

in the correct order (developer first) in addition to

containing the correct solution. Often the lid to the

bottles and the corresponding chemical tanks are

identical in color (

i.e.

bottle with the red lid should

be poured into the red chemical container). The

replacement and replenishment schedule will vary

per office and is based on radiographic workload.

For a normal workload (20 to 30 intraoral films/

day), eight ounces of developer and fixer should

be added to the existing processing solutions

daily after draining approximately the same

amount of used solutions. If over 30 films are

developed per day, then an additional .25 oz/film

should be replenished. Complete replacement of